Rewrite arch/linux (#4352)

* Rewrite arch/linux: interfaces/routes loading

This rewrites much of the arch/linux code, in order to use a RTNETLINK
socket instead of reading /proc/net/XXX.

Among those:
- the read_routes(6) functions
- the linux interfaces provider
- arch/linux util functions

This adds support for multiple IPv4 addresses to interfaces, among with
a generally much better handling of routes.

fixes #4201

* Apply guedou suggestions

* Restrain routes to RT_TABLE_LOCAL and RT_TABLE_MAIN

Author: gpotter2

.config/mypy/mypy_check.py

@@ -63,57 +63,56 @@
     "--ignore-missing-imports",
     # config
     "--follow-imports=skip",  # Remove eventually
-    "--config-file=" + os.path.abspath(
-        os.path.join(
-            localdir,
-            "mypy.ini"
-        )
-    ),
+    "--config-file=" + os.path.abspath(os.path.join(localdir, "mypy.ini")),
     "--show-traceback",
-] + ([
-    "--platform=" + PLATFORM
-] if PLATFORM else [])
+] + (["--platform=" + PLATFORM] if PLATFORM else [])
 
 if PLATFORM.startswith("linux"):
-    ARGS.extend([
-        "--always-true=LINUX",
-        "--always-false=OPENBSD",
-        "--always-false=FREEBSD",
-        "--always-false=NETBSD",
-        "--always-false=DARWIN",
-        "--always-false=WINDOWS",
-        "--always-false=BSD",
-    ])
+    ARGS.extend(
+        [
+            "--always-true=LINUX",
+            "--always-false=OPENBSD",
+            "--always-false=FREEBSD",
+            "--always-false=NETBSD",
+            "--always-false=DARWIN",
+            "--always-false=WINDOWS",
+            "--always-false=BSD",
+        ]
+    )
     FILES = [x for x in FILES if not x.startswith("scapy/arch/windows")]
 elif PLATFORM.startswith("win32"):
-    ARGS.extend([
-        "--always-false=LINUX",
-        "--always-false=OPENBSD",
-        "--always-false=FREEBSD",
-        "--always-false=NETBSD",
-        "--always-false=DARWIN",
-        "--always-true=WINDOWS",
-        "--always-false=WINDOWS_XP",
-        "--always-false=BSD",
-    ])
+    ARGS.extend(
+        [
+            "--always-false=LINUX",
+            "--always-false=OPENBSD",
+            "--always-false=FREEBSD",
+            "--always-false=NETBSD",
+            "--always-false=DARWIN",
+            "--always-true=WINDOWS",
+            "--always-false=WINDOWS_XP",
+            "--always-false=BSD",
+        ]
+    )
     FILES = [
-        x for x in FILES if (
-            x not in {
+        x
+        for x in FILES
+        if (
+            x
+            not in {
                 # Disabled on Windows
-                "scapy/arch/linux.py",
                 "scapy/arch/unix.py",
                 "scapy/arch/solaris.py",
                 "scapy/contrib/cansocket_native.py",
                 "scapy/contrib/isotp/isotp_native_socket.py",
             }
-        ) and not x.startswith("scapy/arch/bpf")
+        )
+        and not x.startswith("scapy/arch/bpf")
+        and not x.startswith("scapy/arch/linux")
     ]
 else:
     raise ValueError("Unknown platform")
 
 # Run mypy over the files
-ARGS += [
-    os.path.abspath(f) for f in FILES
-]
+ARGS += [os.path.abspath(f) for f in FILES]
 
 mypy_main(args=ARGS)

.config/mypy/mypy_enabled.txt

@@ -16,7 +16,8 @@ scapy/arch/bpf/core.py
 scapy/arch/bpf/supersocket.py
 scapy/arch/common.py
 scapy/arch/libpcap.py
-scapy/arch/linux.py
+scapy/arch/linux/__init__.py
+scapy/arch/linux/rtnetlink.py
 scapy/arch/solaris.py
 scapy/arch/unix.py
 scapy/arch/windows/__init__.py

scapy/arch/__init__.py

@@ -125,7 +125,6 @@ def get_if_raw_addr6(iff):
 # Next step is to import following architecture specific functions:
 # def attach_filter(s, filter, iface)
 # def get_if(iff,cmd)
-# def get_if_index(iff)
 # def get_if_raw_addr(iff)
 # def get_if_raw_hwaddr(iff)
 # def in6_getifaddr()

scapy/arch/common.py

@@ -7,12 +7,15 @@
 Functions common to different architectures
 """
 
+import socket
 import ctypes
+
 from scapy.config import conf
 from scapy.data import MTU, ARPHDR_ETHER, ARPHRD_TO_DLT
 from scapy.error import Scapy_Exception
-from scapy.interfaces import network_name
+from scapy.interfaces import network_name, resolve_iface, NetworkInterface
 from scapy.libs.structures import bpf_program
+from scapy.pton_ntop import inet_pton
 from scapy.utils import decode_locale_str
 
 # Type imports
@@ -33,7 +36,6 @@
     "RUNNING",
     "NOARP",
     "PROMISC",
-    "NOTRAILERS",
     "ALLMULTI",
     "MASTER",
     "SLAVE",
@@ -47,6 +49,15 @@
 ]
 
 
+def get_if_raw_addr(iff):
+    # type: (Union[NetworkInterface, str]) -> bytes
+    """Return the raw IPv4 address of interface"""
+    iff = resolve_iface(iff)
+    if not iff.ip:
+        return b"\x00" * 4
+    return inet_pton(socket.AF_INET, iff.ip)
+
+
 # BPF HANDLERS